fix(toml): Remove underscore field support in 2024

src/cargo/util/toml/mod.rs

@@ -349,8 +349,9 @@ fn resolve_toml(
             "dev-dependencies",
             package_name,
             "package",
+            edition,
             warnings,
-        );
+        )?;
         resolved_toml.dev_dependencies = resolve_dependencies(
             gctx,
             edition,
@@ -368,8 +369,9 @@ fn resolve_toml(
             "build-dependencies",
             package_name,
             "package",
+            edition,
             warnings,
-        );
+        )?;
         resolved_toml.build_dependencies = resolve_dependencies(
             gctx,
             edition,
@@ -400,8 +402,9 @@ fn resolve_toml(
                 "dev-dependencies",
                 name,
                 "platform target",
+                edition,
                 warnings,
-            );
+            )?;
             let resolved_dev_dependencies = resolve_dependencies(
                 gctx,
                 edition,
@@ -419,8 +422,9 @@ fn resolve_toml(
                 "build-dependencies",
                 name,
                 "platform target",
+                edition,
                 warnings,
-            );
+            )?;
             let resolved_build_dependencies = resolve_dependencies(
                 gctx,
                 edition,
@@ -657,8 +661,9 @@ fn resolve_dependencies<'a>(
                 "default-features",
                 name_in_toml,
                 "dependency",
+                edition,
                 warnings,
-            );
+            )?;
             if d.public.is_some() {
                 let public_feature = features.require(Feature::public_dependency());
                 let with_public_feature = public_feature.is_ok();
@@ -2323,9 +2328,13 @@ fn deprecated_underscore<T>(
     new_path: &str,
     name: &str,
     kind: &str,
+    edition: Edition,
     warnings: &mut Vec<String>,
-) {
-    if old.is_some() && new.is_some() {
+) -> CargoResult<()> {
+    if old.is_some() && Edition::Edition2024 <= edition {
+        let old_path = new_path.replace("-", "_");
+        anyhow::bail!("`{old_path}` is unsupported as of the 2024 edition; instead use `{new_path}`\n(in the `{name}` {kind})");
+    } else if old.is_some() && new.is_some() {
         let old_path = new_path.replace("-", "_");
         warnings.push(format!(
             "`{old_path}` is redundant with `{new_path}`, preferring `{new_path}` in the `{name}` {kind}"
@@ -2336,6 +2345,7 @@ fn deprecated_underscore<T>(
             "`{old_path}` is deprecated in favor of `{new_path}` and will not work in the 2024 edition\n(in the `{name}` {kind})"
         ))
     }
+    Ok(())
 }
 
 fn warn_on_unused(unused: &BTreeSet<String>, warnings: &mut Vec<String>) {

src/cargo/util/toml/targets.rs

@@ -179,8 +179,8 @@ fn resolve_lib(
     validate_lib_name(&lib, warnings)?;
 
     // Checking the original lib
-    validate_proc_macro(&lib, "library", warnings);
-    validate_crate_types(&lib, "library", warnings);
+    validate_proc_macro(&lib, "library", edition, warnings)?;
+    validate_crate_types(&lib, "library", edition, warnings)?;
 
     if lib.path.is_none() {
         if let Some(inferred) = inferred {
@@ -632,8 +632,8 @@ fn resolve_targets_with_legacy_path(
 
     for target in &toml_targets {
         validate_target_name(target, target_kind_human, target_kind, warnings)?;
-        validate_proc_macro(target, target_kind_human, warnings);
-        validate_crate_types(target, target_kind_human, warnings);
+        validate_proc_macro(target, target_kind_human, edition, warnings)?;
+        validate_crate_types(target, target_kind_human, edition, warnings)?;
     }
 
     let mut result = Vec::new();
@@ -1098,24 +1098,36 @@ fn name_or_panic(target: &TomlTarget) -> &str {
         .unwrap_or_else(|| panic!("target name is required"))
 }
 
-fn validate_proc_macro(target: &TomlTarget, kind: &str, warnings: &mut Vec<String>) {
+fn validate_proc_macro(
+    target: &TomlTarget,
+    kind: &str,
+    edition: Edition,
+    warnings: &mut Vec<String>,
+) -> CargoResult<()> {
     deprecated_underscore(
         &target.proc_macro2,
         &target.proc_macro,
         "proc-macro",
         name_or_panic(target),
         format!("{kind} target").as_str(),
+        edition,
         warnings,
-    );
+    )
 }
 
-fn validate_crate_types(target: &TomlTarget, kind: &str, warnings: &mut Vec<String>) {
+fn validate_crate_types(
+    target: &TomlTarget,
+    kind: &str,
+    edition: Edition,
+    warnings: &mut Vec<String>,
+) -> CargoResult<()> {
     deprecated_underscore(
         &target.crate_type2,
         &target.crate_type,
         "crate-type",
         name_or_panic(target),
         format!("{kind} target").as_str(),
+        edition,
         warnings,
-    );
+    )
 }